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231.
Shunli Ni Sheng Ma Yuhang Zhang Jie Yuan Haitao Yang Zouyouwei Lu Ningning Wang Jianping Sun Zhen Zhao Dong Li Shaobo Liu Hua Zhang Hui Chen Kui Jin Jinguang Cheng Li Yu Fang Zhou Xiaoli Dong Jiangping Hu Hong-Jun Gao Zhongxian Zhao 《中国物理快报》2021,(5):133-137
We systematically measure the superconducting(SC) and mixed state properties of high-quality CsV_3 Sb_5 single crystals with T_c~3.5 K.We find that the upper critical field H_(c2)(T) exhibits a large anisotropic ratio of H_(c2)~(ab)/H_(c2)~c~9 at zero temperature and fitting its temperature dependence requires a minimum two-band effective model.Moreover,the ratio of the lower critical field,H_(c1)~(ab)/H_(c1)~c,is also found to be larger than 1,which indicates that the in-plane energy dispersion is strongly renormalized near Fermi energy.Both H_(c1)(T) and SC diamagnetic signal are found to change little initially below T_c~3.5 K and then to increase abruptly upon cooling to a characteristic temperature of ~2.8 K.Furthermore,we identify a two-fold anisotropy of in-plane angular-dependent magnetoresistance in the mixed state.Interestingly,we find that,below the same characteristic T~2.8 K,the orientation of this two-fold anisotropy displays a peculiar twist by an angle of 60° characteristic of the Kagome geometry.Our results suggest an intriguing superconducting state emerging in the complex environment of Kagome lattice,which,at least,is partially driven by electron-electron correlation. 相似文献
232.
Xin Meng Jinqing Li Xiaoqiang Di Yaohui Sheng Donghua Jiang 《Entropy (Basel, Switzerland)》2022,24(7)
Today, with the rapid development of the Internet, improving image security becomes more and more important. To improve image encryption efficiency, a novel region of interest (ROI) encryption algorithm based on a chaotic system was proposed. First, a new 1D -cos-cot (1D-ECC) with better chaotic performance than the traditional chaotic system is proposed. Second, the chaotic system is used to generate a plaintext-relate keystream based on the label information of a medical image DICOM (Digital Imaging and Communications in Medicine) file, the medical image is segmented using an adaptive threshold, and the segmented region of interest is encrypted. The encryption process is divided into two stages: scrambling and diffusion. In the scrambling stage, helical scanning and index scrambling are combined to scramble. In the diffusion stage, two-dimensional bi-directional diffusion is adopted, that is, the image is bi-directionally diffused row by column to make image security better. The algorithm offers good encryption speed and security performance, according to simulation results and security analysis. 相似文献
233.
用密度泛函B3LYP方法对7种3-(3'-吡啶基)-6-芳基-1,2,4-三唑并[3,4-b]-1,3,4-噻二唑分子进行全优化, 所有化合物都是平面分子. 计算了分子的垂直电子亲和势(VEA)、绝热电子亲和势(AEA)、分子内重组能以及绝对硬度等相关能量, 结果显示化合物的HOMO 与LUMO能级可通过连接不同取代基进行调节, 变化幅度为0.346~1.10 eV. 分子内重组能证实3-(4'-氰基-3'-吡啶基)-6-芳基-1,2,4-三唑并[3,4-b]-1,3,4-噻二唑是很有前途的电子传输材料, 不同取代基所对应的化合物分子内重组能也不同. 绝对硬度数据与分子内重组能都表明, 化合物E, G难于传输电子. 用TDDFT方法计算了化合物A, B和C的吸收光谱, 与实验值相比, 最大吸收峰的差值在3~10 nm之间. 相似文献
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固体酸催化合成邻苯二甲酸二戊酯的研究 总被引:2,自引:0,他引:2
以苯酐和正戊醇为原料,采用自制的固体酸SO4^2-/SiO2、SO4^2-/Fe2O3、SO4^2-/SnO2及SO4^2-/TiO2作为催化剂合成邻苯二甲酸二戊酯(DAP),分别考察固体酸催化剂的种类、固体酸催化剂的用量、醇酐比、反应时间等因素对合成DAP产率的影响。实验结果表明,其优化的工艺操作条件为:苯酐0.1mol,固体酸催化剂SO4^2-/SiO2 1.7g,醇酐比2.4:1,带水剂二甲苯20mL,反应时间3.5h,其产品收率达91.3%以上。SO4^2-/SnO2作为该反应的催化剂具有催化活性高、寿命长、可多次重复使用、产物易纯化分离且产品色泽浅等优点,可望代替传统的浓硫酸作催化剂应用于DAP的合成。 相似文献
237.
Muhammad Arsalan Xiujuan Qiao Azka Awais Yahui Wang Shuying Yang Qinglin Sheng Tianli Yue 《Electroanalysis》2021,33(6):1528-1538
The simple and effective method for the novel synthesis of Pt-based nanoparticle was presented with high efficiency. The sensitive catalyst for the simultaneous detection of catechol and hydroquinone was prepared by depositing ternary metal complex on fluorine-doped tin-oxide (FTO). The composition and morphology of nanomaterials were characterized by TEM, HRTEM, XRD, XPS, and EDS (energy dispersive spectroscopy). The size of the Pt-based nanomaterial was about 5±1 nm. The electrochemical performance of the modified catalyst was studied by CV, DPV, and EIS. The modified PtNiCu@FTO catalyst possessed good electro-oxidation activity for hydroquinone and catechol and used for simultaneous detection of catechol and hydroquinone at scan rate of 20 mV s−1 (vs. Ag/AgCl). Detection responses were found in the ranges of 5–2900 μM for hydroquinone and 5–3000 μM for catechol. The detection limits (LOD) for HQ and CC were observed as 0.35 and 0.29 μM, respectively. The sensitivity of HQ and CC were 1515.55 and 1485 μA mM−1 cm−2, respectively. The prepared nanomaterial were effectively applied for the determination of CC and HQ in real samples. 相似文献
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239.
A combinatorial nickel-catalyzed monofluoroalkylation of aryl bromides with the industrial raw regent ethyl chlorofluoroacetate has been developed. The two key factors to successful conversion are the combination of nickel with readily available nitrogen and phosphine ligands and the using of a mixture of different solvents. Mechanistic investigations indicated a new zinc regent might generated in situ and be involved in the reaction process. 相似文献
240.
Huang Zhiming He Zhimin Ye Yiyong Sheng Xiaokui 《International Journal of Theoretical Physics》2021,60(4):1254-1260
International Journal of Theoretical Physics - Quantum state sharing (QSS) plays significant role in transmitting quantum secret information. However, in practical quantum communication situation,... 相似文献